A.which B.thar C.it D.as
答案是D。在非限制性定語從句中，as可以表示指代前面整句。這裏所缺的關系代詞，恰恰需要能夠指代整句的as。
2.Rose knew that her son dreamed that he could succeed ( ) she had failed.
A.what B.that C.which D.where
答案是D。地點狀語從句，用連接詞where。
3.Mrs Black took the police back to( )place( )she witnessed the robbery.
A.the same;that B.the same ;as C.the same;where D.as the same;as
答案是C。”布萊克女士帶那位警察回到了她目擊搶劫的地方。“place作先行詞，關系詞在從句中充當地點狀語，故用關系代詞where。
4.Nearly all the streets are in straight lines, ( ) from east to west.Those ( ) run from north to south are called avenues.
A.running;that B.run;who C.running ;who D.run ;that
答案是A。running from east to west作伴隨狀語；those are called avenues說明those是物，故用能作主語或賓語的that作關系代詞。